A Study Of SAR/InSAR Real-time Processing And Working Mode Designing

Characterized by day and night and all weather condition working capacity, synthetic aperture radar(SAR) can obtain a two-dimensional image with high resolution by processing the received data. So it has been widely applied in the field of military reconnaissance, remote sensing, resource exploration and so on. Interferometric synthetic aperture radar(In SAR) is a dual antenna radar system developed on the basis of SAR. It observes the same area with different perspectives, thus it can obtain two complex images of SAR. By analyzing the two images with interference treatment, the elevation information of the scattering points in the scene can be extracted, and the digital elevation model(DEM) of the scene can be achieved at the same time. In recent years, In SAR has become one of the hotspots in modern radar research field.In a multi-antenna radar system, because of the effects of mechanical noise,the outer environment and so on, channel errors in amplitude and phase is a problem that has to be taken into account. In a two-antenna In SAR system, the amplitude and phase errors between channels can greatly reduce the coherence of the two complex SAR images and deteriorate the peak side lobe ratio and integrated side lobe ratio, thus the performance of In SAR system is effected ultimately. In view of the problem that amplitude and phase error between channels is inconsistent, this paper explores the specific steps of spectral ratio method and its improved method for amplitude and phase error correction. On the basis of these two methods, this paper puts forward a new method the basic theory of which is adding a window on the signal in frequency. The advantages of this new method are proved by simulation results. On the basis of the simulation results, this paper presents the problem of amplitude and phase error correction in real-time processing system and the new method is used. The real-time processing results verify the feasibility of the proposed scheme.The algorithm of SAR/In SAR is complex, and the amount of data and computation are very large. Therefore, in real-time processing, much more data storage units and arithmetic logic units are greatly needed, and the consumption resources are in large quantities. According to the characteristics of SAR/In SAR imaging system, this paper designs “ping pang” operation mode in order to save the data processing time and hardware resources. In "ping pong" operation mode, the data and parameters of the system are divided into two distributions, at the same time, the data is processed in two distributions——the left path and the right path, too. By using the hardware logic units in different time, the operation time is saved and the stability of the real-time processing system is enhanced at the same time.During the operation of SAR/In SAR imaging platform, its working condition changes constantly. If using the same pulse repetition frequency( PRF) and perspective(?) to process the received data, problems like aliasing and height blurring may appear. In order to get high-quality images, this paper uses the zebra map, combined with the actual operation situation of the platform, dividing the working condition of the platform into several modes. Each working mode corresponds to a specific PRF and ?. In order to meet the need of splicing in subsequent processing, a certain overlap region is set between every two adjacent working modes. At the same time, according to the actual operation situation of the platform, the paper designs two switching methods between the two neighboring modes: normal switching and forced switching. Meanwhile the trigger conditions of the two kinds of switching are expounded. Finally, the real-time processing results of simulation data verify the correctness and feasibility of the design of the working mode.